Study On The Selective Hydrogenation Of Nitriles Catalyzed By Nanoporous Palladium

Primary amine is an important industrial chemical and plays an important role in the field of organic synthesis.It is also an important raw material and intermediate for the preparation of many natural products,drug molecules and fine chemicals.It is widely used in dye,pigment,pesticide,medicine,spices,polyurethane and other industries.Therefore,it is of great significance to develop an efficient,green and safe method for the synthesis of primary amines.Nanoporous metal is a new type of functional nano material,which is composed of nano-scale pores and ligaments.It has the characteristics of high porosity,large specific surface area and good stability.In this paper,the selective hydrogenation of nitriles catalyzed by nanoporous palladium catalysts was studied.Selective hydrogenation of nitriles catalyzed by nanoporous palladium was studied in this thesis.The effects of solvent,catalyst loading,reaction time,reaction temperature and the amount of ammonia borane（hydrogen source）on the conversion of nitriles and the selectivity of primary amines was investigated.The nanoporous palladium catalyst has good stability and high activity,and its catalytic effect will not decrease after being recycled for 10 times.The optimal reaction conditions were as follows:substrate 0.5 mmol,nanoporous palladium catalyst 5 mol%,methanol 3 m L,ammonia borane 1 mmol,reaction temperature 50°C,reaction time 12 h.Primary amines were obtained in 80%-98%yields.In this thesis,the intermittent and continuous hydrogenation of meta-phthalonitrile to meta-xylylenediamine was studied.Experiments were carried out using mechanical reactor and fixed bed to investigate the influence of the catalyst loading,reaction time,reaction temperature,hydrogen pressure and liquid feed flow rate on the conversion and the selectivity of meta-xylylenediamine.The optimal conditions for batch reaction were:substrate（1 mmol）and catalyst（10 mol%）in methanol（10 m L）at 70oC under 5 MPa H₂ for 18 h.The desired product meta-xylylenediamine was obtained in 97%yield.